Stick with it, if you believe in the theory and process of it, you're more than half way there 
Just waft away the annoying flys people who are unsupportive. Their comments will bring you down and make you doubt yourself. I found leaving the BLW book by Gill Rapely lying around quite handy. If criticism came my way, I'd be quite firm that I've read this book, have you? No, well keep your opinions to yourself as this is the way I'm doing things 
This was of course after the 'nicely nicey' approach which had no effect at all
A little 'success' story for you. Dd, now 19 months, BLW from 6 months, she loved food most days and will have odd days of not being so hungry. She didn't use a sippy cup until gone 11 months, but got there in the end, fed herself with a spoon from early on (from memory 8 months) and now eats every single meal we have, sometimes with a spoon or fork, sometimes with her hands. We have never cooked separate meals for her and don't plan on doing so (the odd omelette or pasta if we're having a takeaway later on, otherwise she eats with us)
If she doesn't like something, she picks it off her plate and leaves it there. But she tries things, she enjoys dinner time at the table, there are no battles with her because she knows that we trust her to eat if she's hungry and she is a happy and content little girl.
You may find he eats like a pig one day and not the next, he might like banana today and hate it next week; just keep offering the foods. Dd has only just started eating porridge (even asks for it now) despite refusing it from when we began weaning on to solids 